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Persistently tight damper guide rail bushings

  • 1.  Persistently tight damper guide rail bushings

    Registered Piano Technician
    Posted 06-24-2019 12:54

    Esteemed Colleagues,

    A client has a Boston grand that has had problems with sluggish dampers since day one. The cause is tight damper guide rail bushings.

    A smooth tapered broach, heated with a soldering iron has been used repeatedly.  Pressure has been applied from both ends (top and bottom) of the bushings with an awl. Even the dreaded "umbrella stave" tool has been dug out and used. And yet, on certain particularly stubborn notes, the problem persists.

    So, the question is: What is the next (more drastic) step? Applying VS Profelt, using bridge pins that are considerably larger than the diameter of the damper wire as cauls, and allowing it to sit overnight? Reaming with a similarly oversized bit chucked into either a drill motor or a Dremel (or Foredom) tool? Something else (hopefully, short of re-bushing the entire guide-rail)?

    Also, I would be curious to know if others have encountered this problem on other Boston grands.

    Thanks,

    Alan



    ------------------------------
    Alan Eder, RPT
    Herb Alpert School of Music
    California Institute of the Arts
    Valencia, CA
    661.904.6483
    ------------------------------


  • 2.  RE: Persistently tight damper guide rail bushings

    Registered Piano Technician
    Posted 06-24-2019 13:49
    Alan
    Are you sure it's the damper guide rail bushing that's causing the damper to hang up? I would remove the damper leaver and repin it. Even before that, squirt some Portek on the center and see if that takes care of the problem.

    ------------------------------
    Willem "Wim" Blees, RPT
    Mililani, HI 96789
    ------------------------------



  • 3.  RE: Persistently tight damper guide rail bushings

    Registered Piano Technician
    Posted 06-24-2019 13:57
    Yes Wim, I am certain that the guide rail bushings are the cause of the sluggishness. The center pinning of the underlever flanges is free, as is the top post center pinning. There are no underlever leads walking out to create interference. When the damper wires are disengaged from their set screws in the top flange, there is clearly far more friction on the wires of the problem notes in their guide rail bushings than on notes behaving properly.

    Alan

    ------------------------------
    Alan Eder, RPT
    Herb Alpert School of Music
    California Institute of the Arts
    Valencia, CA
    661.904.6483
    ------------------------------



  • 4.  RE: Persistently tight damper guide rail bushings

    Registered Piano Technician
    Posted 06-25-2019 09:29
    Examine Upstop rail adjustment, generally the cause.




  • 5.  RE: Persistently tight damper guide rail bushings

    Registered Piano Technician
    Posted 06-25-2019 09:54
    Hi Timothy,

    How is it that the damper up-stop rail could cause the mis-behavior I have described? If it's too high, might that allow the wire-to-bushing geometry to become extreme, causing the binding? And as I said to Ed McM., how would your scenario explain why the damper wires eventually become tight again after easing?

    Alan

    ------------------------------
    Alan Eder, RPT
    Herb Alpert School of Music
    California Institute of the Arts
    Valencia, CA
    661.904.6483
    ------------------------------



  • 6.  RE: Persistently tight damper guide rail bushings

    Registered Piano Technician
    Posted 06-26-2019 10:06
    If damper upstop is too high, the tabs can hang on the sostenuto blade.

    —Cy—




  • 7.  RE: Persistently tight damper guide rail bushings

    Registered Piano Technician
    Posted 06-26-2019 10:27
    Cy,

    Thanks for offering a response to my question to Timothy. Following your line of explanation, if the damper unstop railI were too high, I could see sostenuto tabs getting stuck on the sostenuto knife when it is engaged. Do you mean that the sos. tabs could also get stuck when the knife is at rest, if the unstop rail is too high? Just curious.

    Nevertheless, I am convinced that the damper guide rail bushings are the culprit on this piano.

    Alan

    ------------------------------
    Alan Eder, RPT
    Herb Alpert School of Music
    California Institute of the Arts
    Valencia, CA
    661.904.6483
    ------------------------------



  • 8.  RE: Persistently tight damper guide rail bushings

    Registered Piano Technician
    Posted 07-24-2019 10:33
    Alan said:
    "...if the damper unstop railI were too high, I could see sostenuto tabs getting stuck on the sostenuto knife when it is engaged. Do you mean that the sos. tabs could also get stuck when the knife is at rest, if the unstop rail is too high? Just curious."

    It's certainly possible, depending on the size of the tabs and the adjustment of the blade (knife). Many times the blade doesn't have much clearance at rest, and the fore/aft position of the tabs can vary.

    On rebushing guide rails, I was taught to refinish the wooden guide with lacquer before bushing, and then to size the bushings with alcohol/water and usually a #7 bridge pin. The alcohol will soften the lacquer and then glue the bushings in place.

    -Cy-






  • 9.  RE: Persistently tight damper guide rail bushings

    Registered Piano Technician
    Posted 07-24-2019 15:18
    Hi Cy,

    Nice to see you at the convention!

    Over the Fourth of July weekend I visited the piano in question, loaded for bear (i. e., prepared to do everything everyone suggested, short of rebushing the rail in the customer's home). As usual, I started with the simplest, least intrusive option that did not preclude doing any of the other stuff if it didn't work. First, I confirmed that the problem was, indeed, tight DGR bushings. The first option was to apply VS Profelt to the damper guide rail bushings, withOUT removing the dampers. This was suggested by someone who has had previous experience with this particular problem on this particular brand but, like several other individuals, decided to communicate via PM only. 

    It is now three weeks out, and all indications are that it worked! For all of the obvious reasons, this option was far less labor intensive than anything that involved removing and replacing the dampers. I was at the client's home over a two day period (doing other work on the piano, and hiking in Joshua Tree!), so if another approach was needed, there would have been time for it. Not necessary.

    In the event that the problem returns to this piano, I will let this list know.

    Thanks again, to everyone who responded in a constructive way, for all of your input. Three cheers for the high-quality of collaboration at which our species excels!!!

    Alan


    ------------------------------
    Alan Eder, RPT
    Herb Alpert School of Music
    California Institute of the Arts
    Valencia, CA
    661.904.6483
    ------------------------------



  • 10.  RE: Persistently tight damper guide rail bushings

    Registered Piano Technician
    Posted 07-24-2019 15:31
    I recently heard that Steinway no longer regulates damper wires to bear against one side of the DGR hole.  I have no idea if Boston ever did, or still does.  Not that this affects your damper situation.

    So great to see you and many others at the Convention!

    Regards,
    Zeno

    ------------------------------
    Zeno Wood
    Brooklyn, NY
    ------------------------------



  • 11.  RE: Persistently tight damper guide rail bushings

    Registered Piano Technician
    Posted 07-24-2019 18:24
    Thanks Zeno. I was not taught that in Piano Technology and never really "bought into that". I have not let it "bother me" if some do sort of rub the guide bushing a bit as long as there is not too much friction, etc etc. 
    Good to know.

    ------------------------------
    [Kevin] [Fortenberry] [RPT]
    [Staff Techician]
    [Texas Tech Univ]
    [Lubbock] [TX]
    [8067783962]
    ------------------------------



  • 12.  RE: Persistently tight damper guide rail bushings

    Registered Piano Technician
    Posted 07-24-2019 19:21
    Having the wire bear on the side of the bushing was definitely taught by both Kent and Eric Schandall in the 2005 - 2010 period. And the bushings were quite thin, leaving ample room for the wire (they couldn't support the wire well in the middle of the bushing). So it is interesting that they have changed, probably a Hamburg thing.
    Regards,
    Fred Sturm
    "Travel is fatal to prejudice, bigotry, and narrow-mindedness." Twain






  • 13.  RE: Persistently tight damper guide rail bushings

    Registered Piano Technician
    Posted 07-24-2019 19:36
    A detail from Kent and Eric: the bottom bend was called the "pressure bend," the top the "travel bend." IOW, the bottom pressed the wire against the side, while the top aligned the wire to move vertically. It's a good concept, whether or not you regulated to have the wire bear on one side.

    Me, I definitely do make all my wires bear to the side, for many reasons. Chief among them is good damping: the pressure against a support (as opposed to relying on the wire in the top flange below the guide rail) adds considerably to the stability of the damper head in contact with vibrating strings. Another is the fact that the heads won't move fore/aft during pedaling, something likely to occur when they are only held by the top flange - mostly looks bad, but also means that the damper isn't held as firmly against the string. Third is the impossibility of binding because of the bushing pressing in on all sides, and thereby needing easing.

    The caveat is that the pressure bend must be made with finesse and care. Just enough to spring against the bushing when the wire is sprung in the other direction (with a finger while regulating). Not enough to cause drag. You can get a good sense for that while regulating by lightly raising each damper and feeling drag when it drops (slightly supporting it on the down stroke), and also by doing a stroking motion of the damper lever with a finger (finger bending upwards, pulled toward you so it slips off the lever), raising and letting it drop rapidly. The speed of fall, plus a wee bit of noise, tells the tale.

    Also, the travel bend thing is a very useful way of taking a fairly chaotically set of dampers and getting them aligned. Of course you also have to deal with the top bends, setting the position of the damper head relative to the strings.

    It works for me, could work for you. I have no particular quarrel with the other system, other than the thought that I really don't have to worry about easing bushings. I just lubricate of do a minor tweak of the pressure bend if there is friction, which I find more efficient. 
    Regards,
    Fred Sturm
    "When I smell a flower, I don't think about how it was cultivated. I like to listen to music the same way." Mompou






  • 14.  RE: Persistently tight damper guide rail bushings

    Registered Piano Technician
    Posted 06-24-2019 14:09
    I have next to no Boston experience, but I would wonder if the wires are leaning to one side (as in Steinway methodology), or held in the middle from both sides (Yamaha methodology). If they lean, a tiny change in the bottom bend can relieve the problem.

    I made an umbrella stave tool for soldering iron: drilled a hole in 1/4" brass rod, inserted the stave, hammered a bridge pin in the curve. I have carefully filed/tapered the stave, so it goes in smoothly. Press against the wire while inserting. This means I can iron the bushings without removing the dampers. First try just in and out. If that doesn't work, try rotating it back and forth around the wire, pressing in more deeply.

    Why a tapered broach? I have a couple homemade broaches (friction fit in 1/4" brass) with different sized bridge pins for use with a soldering iron. Try one, if it isn't enough, use the thicker one. 

    I assume it isn't a lubrication problem (that you would have checked), but that is also a possibility. Remove keyframe, depress damper pedal, run an artist brush with ProLube or the like along the wires above the guide rail. Move pedal up and down, maybe repeat.

    Rebushing guide rails isn't all that bad. 
    Regards,
    Fred Sturm
    "I am only interested in music that is better than it can be played." Schnabel






  • 15.  RE: Persistently tight damper guide rail bushings

    Registered Piano Technician
    Posted 06-24-2019 14:21
    Fred,

    The damper wire/guide rail bushing cloth arrangement is "Yamaha methodology" (i. e., no leaning against one side of the bushing a la Steinway).

    Your stave tool for soldering iron sounds like a great idea. I'll have to give it a try. 

    "Why a tapered broach?" you ask. Because I made one (tapering from ~.065" to ~.078") years ago that has solved every tight guide rail bushing problem I have encountered, until now.

    Thanks for mentioning lubrication. I forgot to mention in my OP that I have also tried that, but it does not solve the problem.

    And yes, I agree that rebushing guide rails isn't all that bad. It's just the most labor intensive option. 'twould be a pity to have to do it on a relatively new piano.

    Alan

    ------------------------------
    Alan Eder, RPT
    Herb Alpert School of Music
    California Institute of the Arts
    Valencia, CA
    661.904.6483
    ------------------------------



  • 16.  RE: Persistently tight damper guide rail bushings

    Registered Piano Technician
    Posted 06-24-2019 16:59
    Hi Alan, I have several example of nice grand pianos with this exact issue..some several tech were unable to correct. (one case in particular was a new Baldwin L nearly 20 years ago-super nice home...really nice piano in walnut..numerous avid musicians in the family!) 
    Resizing the guide bushing with a #8 bridge pins corrected the problem immediately. Back then I resized with alcohol & water but now I just use heat with the #8 bridge pins. ​​I hold the bridge pin in the candle lighter flame (with meddle nose pliers) & count to 10..so about 10 seconds... then slowly insert in from the bottom using a battery light laying on top so I can see well. By the time the pin goes into to the hole it has cooled down enough to not scorch the bushing, but still plenty hot to resize the bushings. I usually do about a dozen then begin reusing the ones which have now cooled down. It really flows well once you get going. The Re-insert & regulate dampers. 
    (I usually rub the area of the damper wire with a piece of 4 ought steel wool & then usually apply a bit of dry film as well. But the Method works just fine on newer parts without the dry film. That's just how I roll. 
    Hope this helps! Kevin

    ------------------------------
    [Kevin] [Fortenberry] [RPT]
    [Staff Techician]
    [Texas Tech Univ]
    [Lubbock] [TX]
    [8067783962]
    ------------------------------



  • 17.  RE: Persistently tight damper guide rail bushings

    Registered Piano Technician
    Posted 06-24-2019 17:05
    Thanks for the benefit of your experience, Kevin. I'll give the heated bridge pins as caul method a try.

    Alan

    ------------------------------
    Alan Eder, RPT
    Herb Alpert School of Music
    California Institute of the Arts
    Valencia, CA
    661.904.6483
    ------------------------------



  • 18.  RE: Persistently tight damper guide rail bushings

    Registered Piano Technician
    Posted 06-24-2019 18:11
    Sounds good Alan. One small caveat..(and of course I meant "NEEDLE nose" pliers)...# 8 bridge pins seems a bit large according to "specs" .. but if we are already having an issue then just a tad extra leeway is exactly what is needed. Then...you have just a little wiggle room as humidity WILL increase and "poof" then back up a bit...so anyway..I stand by this.

    ------------------------------
    [Kevin] [Fortenberry] [RPT]
    [Staff Techician]
    [Texas Tech Univ]
    [Lubbock] [TX]
    [8067783962]
    ------------------------------



  • 19.  RE: Persistently tight damper guide rail bushings

    Registered Piano Technician
    Posted 06-24-2019 18:20
    Kevin,

    One would think that a #6 bridge pin (~.075") should do the job, but something much larger may well be in order for this piano. I can start with a smaller heated bridge pin and work my way up​. And if #8s don't turn the trick (at ~.093"), there are always the #9s and #10s!

    Alan​​​

    ------------------------------
    Alan Eder, RPT
    Herb Alpert School of Music
    California Institute of the Arts
    Valencia, CA
    661.904.6483
    ------------------------------



  • 20.  RE: Persistently tight damper guide rail bushings

    Registered Piano Technician
    Posted 06-25-2019 06:21
    If the bushings are dense and tight, how about removing the dampers and reaming them? Roughen a #7 pin or nail of similar size and remove some material, then iron the bushings. Dip a pointy dowel in teflon powder and apply to all bushings. Clean the damper wires and lube them with tfl-50, mclube 444, or prolube.

    ------------------------------
    Mario Igrec, RPT
    http://www.pianosinsideout.com
    ------------------------------



  • 21.  RE: Persistently tight damper guide rail bushings

    Registered Piano Technician
    Posted 06-25-2019 09:45
    Hi Mario,

    Both you and Ed Sutton are thinking along the same lines. Reaming, burnishing and lubricating on on the, "if that don't work, try this"  list, right after sizing.

    Thanks,

    Alan

    ------------------------------
    Alan Eder, RPT
    Herb Alpert School of Music
    California Institute of the Arts
    Valencia, CA
    661.904.6483
    ------------------------------



  • 22.  RE: Persistently tight damper guide rail bushings

    Member
    Posted 06-25-2019 18:29
    Hi Alan,

    I'm a bit late to the party here, but I didn't see it written elsewhere so I will add this.  A technician once told me that wool has memory, and that if you try to resize/reshape any kind of wool that moisture should be part of the equation.  I don't know what the science is to "memory" in wool fibers, but I do know that my experience has generally confirmed this fact.

    I've always had a tougher time resizing key bushings with a dry soldering iron approach.  The same has been true for a soldering iron insert that I've made specifically for guide rail bushings.  In both cases, the bushings always find a way of fluffing back up, so to speak.  I think resizing with Profelt (which I've had good results with key bushings and guide rail bushings alike) or alcohol and water (using a suitable sized "caul") would both be sufficient, in my opinion.  I believe Profelt is primarily alcohol and water with a bit of silicone lubricant anyways.

    With regard to a broach (roughed up damper wire?) method (similar to the "Mannino style" broaches), I've used that method in the field with some success as well.  It seemed prudent in the field to deal with one or two, but I've never done an entire set that way.

    Hope this adds to the conversation.  Best of luck!

    Peace,

    Luke

    ------------------------------
    Luke Taylor
    North Hollywood CA
    310-386-7014
    ------------------------------



  • 23.  RE: Persistently tight damper guide rail bushings

    Registered Piano Technician
    Posted 06-25-2019 18:53
    Good point about adding moisture to the mix. One way of doing that would be to wet the bushings somewhat before ironing. One method I can imagine is using an artist brush on each, insinuating a drop of water into each bushing. Do them all, then follow with heated caul. 

    Experiment on one or two first, to see if it works. If you have a small enough brush, it can penetrate the bushing. 

    Profelt would probably work, but it means getting the bushings fairly wet, inserting a pin, leaving over night, returning. And a hotter broach would create steam, which would likely shape the felt more permanently. Steam sizing key bushings is a very stable procedure.
    Regards,
    Fred Sturm
    "A mind is not a vessel to be filled, but a fire to be kindled." Plutarch













  • 24.  RE: Persistently tight damper guide rail bushings

    Registered Piano Technician
    Posted 06-25-2019 22:37
    Your post most certainly DOES add to the conversation, Luke. Thanks for stepping into the light on this one!

    Point of clarification: Do you use cauls with both the VS Profelt and the alcohol/water solution?

    Alan



    ------------------------------
    Alan Eder, RPT
    Herb Alpert School of Music
    California Institute of the Arts
    Valencia, CA
    661.904.6483
    ------------------------------



  • 25.  RE: Persistently tight damper guide rail bushings

    Member
    Posted 06-26-2019 00:10
    Hi Alan,

    To clarify, I have not used alcohol and water in this instance, but I believe it would have a similar effect to VS Profelt (i.e. without the benefit of the added lubricant I suppose, if there is a benefit).  For cauls, I've used nails of the appropriate size as they were quicker to get from the hardware store (I just went there with a caliper and searched around the bins for the appropriate diameter).

    Peace,

    Luke

    ------------------------------
    Luke Taylor
    North Hollywood CA
    310-386-7014
    ------------------------------



  • 26.  RE: Persistently tight damper guide rail bushings

    Registered Piano Technician
    Posted 06-26-2019 07:19
    Luke,

    More follow-ups:

    1) How much larger than the damper wire diameter (~.072") were the nails you used as cauls?

    2) What is the shortest amount of time you have ever successfully allowed between applying the Profelt and reassembling the damper(s)?

    Thanks,

    Alan


    ------------------------------
    Alan Eder, RPT
    Herb Alpert School of Music
    California Institute of the Arts
    Valencia, CA
    661.904.6483
    ------------------------------



  • 27.  RE: Persistently tight damper guide rail bushings

    Member
    Posted 06-26-2019 09:22
    1) It's been several years but I believe I used an .080 diameter nail.

    2) When using VS Profelt I've always given it ~24 hours.


    ------------------------------
    Luke Taylor
    North Hollywood CA
    310-386-7014
    ------------------------------



  • 28.  RE: Persistently tight damper guide rail bushings

    Registered Piano Technician
    Posted 06-26-2019 09:31
    Roger that, Luke. Thanks!

    Alan

    ------------------------------
    Alan Eder, RPT
    Herb Alpert School of Music
    California Institute of the Arts
    Valencia, CA
    661.904.6483
    ------------------------------



  • 29.  RE: Persistently tight damper guide rail bushings

    Registered Piano Technician
    Posted 06-26-2019 11:21
    Alan,

    We have had long-term success with Profelt and #7 bridge pins.  Between the sizing qualities of the water and the lubrication, we have not seen sluggishness return to guide rails.  This is similar to our key bushings.  Once sized with Profelt, bushings stay tighter (I hate sloppy keys) and last longer than any other process we have tried in the past.  On a side note, we have been experimenting with Profelt on tight Renner flanges.  It is too early to judge longevity, as we are only a few months in, but this looks promising.  Once the bushings in hammer flanges dry 24 hours, the friction is fairly consistent at 10-12 swings (~1 g).  I prefer a little more friction in hammers (3-4 g), so we usually follow up with repinning.  The treated bushings are much more consistent and pinning time is cut in half.  Early indications are that this is a viable procedure for us, but, as I said, it is a little early to commit to that.

    Rick​

    ------------------------------
    Rick Florence
    Gilbert AZ
    ------------------------------



  • 30.  RE: Persistently tight damper guide rail bushings

    Registered Piano Technician
    Posted 06-26-2019 11:31
    Rick,

    Thanks so much for adding your voice to the chorus of those others--Karl, Linda, & Luke--who successfully use Profelt on guide rail bushings.

    And what a wonderful bonus to learn of your experimentation with Profelt on seized-up Renner action center bushings! How fortunate for the rest of us that you are doing this and sharing your observations.

    Alan

    ------------------------------
    Alan Eder, RPT
    Herb Alpert School of Music
    California Institute of the Arts
    Valencia, CA
    661.904.6483
    ------------------------------



  • 31.  RE: Persistently tight damper guide rail bushings

    Registered Piano Technician
    Posted 06-26-2019 10:29
    Consider also the guide rail itself.  Am appreciating all the suggestions regarding the condition of the felt to wire combinations and all have good merit.

    While I don't have data to confirm my suspicions, let's also consider the moisture content of the wooden rail.  I find in my rebuilding experience that many, many guide rails have little to no finish on them.  Care to add sufficient finish to the rail may help with moisture exchange between the felt and the wood.  One would think that in a glued bushing scenario that this would be minimal but we are talking very tight tolerances here.  Any good lacquer/polyurethane finish should help with the situation.  Looks very pro as well.

    Mike Reiter

    ------------------------------
    Michael Reiter
    Eugene OR
    541-515-6499
    ------------------------------



  • 32.  RE: Persistently tight damper guide rail bushings

    Registered Piano Technician
    Posted 06-26-2019 10:42
    Interesting thought about moisture exchange between an unfinished damper guide rail and the guide rail bushing cloth. So you glue in your damper guide rail bushings, like a center pin bushing? I never have, personally. And I don't know what was done in the factory on this Boston.

    Thanks, Mike,

    Alan

    ------------------------------
    Alan Eder, RPT
    Herb Alpert School of Music
    California Institute of the Arts
    Valencia, CA
    661.904.6483
    ------------------------------



  • 33.  RE: Persistently tight damper guide rail bushings

    Registered Piano Technician
    Posted 06-26-2019 11:57
    I too put a small amount of glue on damper guide rail bushings. And I too have had good success with profelt and nails the size of #7 bridge pins. Profelt seems to stabilize the bushings there and in keys too. Improves longevity and performance of those felts.​

    ------------------------------
    Mario Igrec, RPT
    http://www.pianosinsideout.com
    ------------------------------



  • 34.  RE: Persistently tight damper guide rail bushings

    Registered Piano Technician
    Posted 06-26-2019 12:18
    Check, check and check, Mario!

    Alan

    ------------------------------
    Alan Eder, RPT
    Herb Alpert School of Music
    California Institute of the Arts
    Valencia, CA
    661.904.6483
    ------------------------------



  • 35.  RE: Persistently tight damper guide rail bushings

    Posted 06-26-2019 13:41
    I have always followed Bill Garlick's  1982 tutelage and put a dab of hide glue when re-bushing  damper guide rails before 'chasing' the cloth through the  rail hole, if  subsequently in the field  any easing is necessary with whatever tool how bloody annoying is it to have an unglued bushing pop right out!  also  in preparation of the rail  to answer another query I have always applied at  least a coat of lacquer sanding sealer on the newly sanded rail.

    ------------------------------
    Martin Snow
    South Burlington VT
    617-543-1030
    ------------------------------



  • 36.  RE: Persistently tight damper guide rail bushings

    Registered Piano Technician
    Posted 06-27-2019 14:34
    Yes, I too am a proponent of the slightly glued bushing.  

    In thinking back to a number of pianos and Boston may be one of those, the flange portion of the damper guide rail is often way too thick.  Not only does it increase the surface contact of the wire to the bushing but also if there is any scenario where the wire is other than 90 degrees to the hole, binding may occur.  

    I have found many of these DGRs not properly prepared in my view.  If we look at many of the older Steinways the DGR is quite thick but is countersunk from both the top and bottom.  This gets us to a minimal contact between the wire and the bushing and eliminates problems with wires that are not perpendicular as they are supposed to be.  Expansion and contraction is held to a minimum and if one wishes to install the bushing sans glue there is less chance of pushing the bushing out of its place.  

    We can take a modern DGR and countersink from both sides as well but must maintain a 1.5-2mm shelf to define the actual diameter of the hole for accurate sizing.  Reduces the noise as well.  This of course requires a rebushing of the DGR but have we not solved for many of the above problems in doing so?  Yes, still size the hole by your favorite method and be absolutely sure to select the right size of bushing cloth as well!!!

    Mike

    ------------------------------
    Michael Reiter
    Eugene OR
    541-515-6499
    ------------------------------